Hydraulic back-pressure gas valve



July 8,1930. j L. oLlPHANT 1310,34

I HYDRAULIC BACK Pnn ssunrus ALVE.

Filed M55 26/1922 I lief. passage.

Patented July 8,

UNITED STATES PATEN T oFFrcE LAURENCE OLIPHANT, 0F TRENEIION, NEW JERsEY, ASSIGNOR TO/ OXWELD' AGETYLENE COMPANY, A CORPORATION OF WEST VIRGINIA.

HYDRAULIC BACK-PRESSURE GAS VALVE f I Application filed May 26, 1922. Serial No. 563,843.

This invention relates to an improved hysumingmea ns,e. g.,' a blowpipe. To prevent draulic back pressure gas valve for use prinbackfire and reverse flow of gas through the I cipally in connection with metal heating, valve to the gas supply line feeding to the ,weldingand cutting blowpipes to prevent oxygen or air from backing into the lower pressure fuel-gas supply line, as in case of accidental stoppage ofthe blowpipe tip, and to prevent blowpipe flash-backs from entering the fuel-gas supply line. 1

Fundamentally, this invention follows the one disclosed in United States Patent N 0. 1,108,863 in which the oxygen or air that backs into the valve builds up a pressure which is vented to the atmosphere at a predetermined pressure through a gas relief passage normally sealed by a liquid column in the valve. During this venting the fuel-gas supply pipe is sealed by the liquid column and after venting the liquid seal is automatically restored to again seal the pressure re- Separate tubes are provided in the valve of the aforesaid patent to relieve the pressure and to return the liquid entrained by the vented gas to restore the seal. The primary objectof the present invention is to, simplify the prior construction described and thereby provide a very satisfactory but less expensive valve. The principal feature of this invent1on consists in the replacement of the aforesaid separate tubes by a singletube that serves the two-fold purpose of a gas vent and a liquid return passage. The objects and novel features of this invention willbe apparent from the following description taken with the drawings in which Fig. 1 is a-central longitudinal sectional view of a back pressure valve embodying this invention, and

Fig. 2 is a transverse sectional view of the same, taken along the line 22 of Fig. l.

As shown in the drawings, the valve has a main or lower chamber L and an auxiliary or upper chamber U, such chambers being separated by a partition P. Fuel gas, such as acetylene, city gas and .the. like, may enter the lower chamber through suitable inlet means,-

tube I the chamber is constructed to contain a column of suitable liquid W, such as water or kerosene, which has its level at a predetermined height above the inlets 9.( When such backfire or reverseflow of gas builds up a pressure in the valve, liquid rises in the tube T and also in the tube I and keeps them sealed, and at a predetermined pressure-the entrance of a vent tube T i uncovered by the depression ofthe liquid evel, permitting the escape of gas from the chamber L until equilibriis restored in the valve. The gas thus vented carries out some sealing liquid which, if lost, would in time render the seal and valve ineffective, so this entrained liquid is intercepted in the upper chamber U and returned to" the lower chamber through the vent tube; the latter thus constituting a com bined pressure-relief and liquid-return tube. v

- In the advantageous embodiment of 'the invention illustrated in the drawings, the

casing of the improved valve comprises axially alined upper. and lower tubular sections v 10 and 11 secured to the partition P, and

closed by end caps 12 and 13. The inlet tube I extends centrally through the entire casing and may have threaded ends fitting and projecting through threadediholes in the of the cap 13, and the gas outlet 0 may be at a suitable distance above the gas inlets 9 and in a nipple secured in an opening in the casin section lland to which a hose connection may be coupled. j

The level of theliquid column W is deas by a gas inlet tube I which has one or more sirably maintained at about the levelof the holes or inlets 9; and the gas may flow out of lower part'of the bushing 18 that is secured the valve through an outlet 0 to the gas-conin the casing section 11150 provide a,

fill the valve with liquid.

2 opening,

tenda-nt to very readily inspect and properly The'lower' end of the improved vent tube T communicates with or opens into the compartment L a short distance above the inlets 9 but is normally sealed b the liquid column 7 in this, compartment. T e'tube T is desirably surrounds and is concentric with the inlet tube I, providing an annular passage 21 between these tubes that extends to an opening in the central lowest part of the partition P to which the. upper end of the tube T is joined, as by threads 22., When back-fire or back-pressure builds up a predetermined ressure in the chamber L, the lower end of the tube T will be uncovered and relieve such pressure by allowing the escape of gas' through the passage 21 in the tube T into the v chamber U which communicates with the at be dish-shaped as shown to mosphere through the openings It in the end ca i ome liquid is carried through the tube T with the vented gas and, in order to pre-'' vent the loss of all this liquid, it is intercepted in the chamber U and returns throu h the same tube T to the chamber L when tie back pressure has been relieved. Atthe same time, the liquid that has been forced u into the tube I also returns to the'chambe'r the normal liquid level restoring and coverin the lower end of the vent T. Liquid carrie up through the passage 21 may be intercept-' ed by a baflie plate 23 secured to the tube I with its central part directl above the passage 21 so that the stream 0 liquid-carrying vented gas will meet equal baflie areas on all sides and the liquid will be more completely precipitated onto the partition P, which may 7 better conduct thisliquid into the upper end of the passage 21. The baflie 23 may be circular, of greater extent than the part of the cap 12 that contains the holes R, and of inverted dish shape. In order that fuel-gas entering the compartment L through the inlets 9 shall be prevented from bubbling straight up and out through the passage 21, a deflector plate 25 is arranged between the inlets 9 and the lower end of the passage 21. This deflector may be circular and centrally secured to the tube I, as shown( Solder or other suitable securing means may of course be employed to unite the various parts of the valve and provide.

gas and liquid tight joints where desired.

While the invention is shown and described liquid and having its u bottom and open to the atmosphere at the top.

2. A hydraulic back pressure gas valve comprising a casing having two compartments separated by a partition, the main compartment having a gas outlet, a gas inlet tube having its inlet in said main compartment adapted to be sealed by liquid, and a vent tube communicating with the main compartment above the inlet of said inlet tube but normally sealed by such liquid, said vent tube being secured to said partition and surrounding said inlet tube and alsoproviding a return passage for liquid carried into the other compartment by vented gas.

3. A hydraulic back pressure gas valve comprising a casing Having upper and lower compartments separated by'a partition, the lower compartment having a gas outlet, a gas inlet tube 1 extending centrally through said compartments and said partition and having its inlet in the lower compartment adapted to be sealed by liquid to prevent reverse flow of gas, a vent tube concentric with said inlet tube and communicating with both compartments, said vent tube being normally sealed by such per end secured to said artition,.. and a ba e plate mounted on said Inlet tube centrally above said vent tube. 4. A hydraulic back pressure gas valve comprisinga casing having upper and lower compartments separated by a partition, the lower compartment having'agas outlet and 1 the uppercompartm'ent having gas relief outlet means,.a gas inlettube extending centralcombined gas-vent and liquid-return tube extending along said gas inlet tube and cominunicatmg with the upper compartment and also with the lower compartment above the outlet of'said inlet tube but normally also sealed by such liquid, a deflector mounted on the inlet tube between the outlet of said inlet tube and the inlet of said vent tube with its .central part opposite the latter inlet, and a baflle mounted on the inlet tube with its central part above the upper end of the vent tube. In testimony whereof, I affix my signature.

LAURENCE OLIPHANT. 

